Apple Insider has scrounged up an Apple patent, filed in late 2007, that just, you know, immediately clicks. It's for instant media sharing during iPhone calls, and it makes plain old video calling look downright boring.

The application explains it thusly:

An individual may call his friend to discuss music, but in order for the friend to listen to the music, the individual either may have to send the music to the friend using a device other than his telephone, or he may have to end the phone call and use the telephone to send the friend an email with the music attached.

This capability extends to pretty much anything, from photos and videos to voicemail and "others", and implies that the data could be streamed in real time, not just transferred and downloaded.

Carrier reluctance and technical network limitations are the most obvious obstacles to something like this actually coming to pass in the near future, though the patent has a clever solution for the latter problem:

There may also be two audio data streams to transmit. In order to transmit all of the streams over the same communication path, the control circuitry may employ a multiplexer to combine together any video streams, and to combine together any audio streams, the multiplexer may then combine into one fixed stream the two combined streams.

In other words, this is more than an airy-fairy "wouldn't it be cool" concept—Apple seems to have given it some serious thought, and a bit of real engineering attention. And the more the better: this is one of those concepts that, once you see it, just seems like it needs to happen. [AppleInsider]